Roughly a third of our future electricity demand will be for home and office heating – amounting to an approximately 50 gigawatt peak requirement. Air source and ground source heat pumps are being proposed to be the major provider of this heat. But is this realistic?
Ground source heat pumps require digging up substantial pieces of land surrounding the property; this adds to cost and means they are useless for flats and office accommodation.
Air source heat pumps seem to be the answer, but they do not work very well when the outside temperature is less than 5°c. Many people have to use supplementary heating with gas or oil to keep warm. This, of course, is not carbon friendly.
The answer is to insulate homes more effectively, but for most homes this is impractical. Already the cost of the heat pump installation is £15,000 to £20,000 and adding another £20,000 or £30,000 for better insulation is unthinkable for most people. The efficiency of heat pumps is roughly half that of a gas boiler because the working fluid is typical of that used in refrigerators and only operates at 37°c, as opposed to 70°c for water in gas boilers.
So, the large part of the electricity used to drive a typical household heat pump is wasted compared to a gas boiler with similar power rating. The conclusion is that the move to heat pumps is going to be impossibly expensive, and will be less energy-efficient than with current gas boilers.
The best solution is to use green hydrogen in a gas boiler. This means that all homes can carry on much as before but with hydrogen as fuel. This hydrogen can be manufactured by electrolysis from water, and emits no CO2 when combusted. The only issue is that large amounts of electricity are required.
Which brings us to the core issue: how can we produce electricity economically from green sources in the quantities that we require? Adding requirements for transport and industry, and hydrogen production, to that for heating adds up to a 150 gigawatt peak demand.
Sadly, Britain’s electrical energy provision policy has been non-existent for the past 30 years. In response to the zero carbon initiative, ministers have invested in renewable sources of energy at the expense of the public and common sense.
They have argued that renewable energy is cheap, but it isn’t, as the green levies on our electricity bills are now telling us. They have been unable to comprehend that renewable energy is intermittent, so that we cannot rely on it to provide stable supplies of electricity to run our industry, to run our cars, and to heat our homes.
So, what are our alternatives? In the growing realisation that renewables are not the answer, gas has come back into favour, even though it produces vast amounts of CO2. Now, due to the activities of Mr Putin, amongst others, gas is becoming a strategic weapon, and we are faced with hugely increased energy bills if we continue to burn gas to produce electricity.
Because of our lack of energy policy we seem incapable of making proper, appropriate, investment decisions to benefit the country. Rolls Royce could produce 100 modular nuclear “pressurised water reactor” systems in the time that it is going to take to finish Hinkley Point C and Sizewell C. This would produce stable, economically attractive, green electricity that the country now so desperately needs.
Roy Faulkner is emeritus professor of materials engineering at Loughborough University and has wide experience in the energy industry, particularly with coal and nuclear, and the drive to reduce emissions. He is currently a consultant with the Nuclear Decommissioning Authority.